Secreted Frizzled related protein-4 (sFRP4) promotes epidermal differentiation and apoptosis.
The skin provides vital protection from infection and dehydration. Maintenance of the skin is through a constant program of proliferation, differentiation and apoptosis of epidermal cells, whereby proliferating cells in the basal layer differentiating to form the keratinized, anucleated stratum corneum. The WNT signalling pathway is known to be important in the skin. WNT signalling has been shown to be important both in epidermal development and in the maintenance and cycling of hair follicles and epidermal stem cells. However, the precise role for this pathway in epidermal differentiation remains unknown. We investigated the role of the WNT signalling inhibitor sFRP4 in epidermal differentiation. sFRP4 is expressed in both normal skin and keratinocytes in culture. Expression of sFRP4 mRNA and protein increases with keratinocyte differentiation and apoptosis, whilst exposure of keratinocytes to exogenous sFRP4 promotes apoptosis and expression of the terminal differentiation marker Involucrin. These data suggest sFRP4 promotes epidermal differentiation.
Maganga
Richard
R
School of Anatomy and Human Biology, University of Western Australia, Perth, WA, Australia.
Giles
Natalie
N
School of Anatomy and Human Biology, University of Western Australia, Perth, WA, Australia; The McComb Research Foundation, Telstra Burn Outcome Centre, 11th Floor, Royal Perth Hospital, Wellington Street, Perth, WA 6000, Australia.
Adcroft
Katharine
K
School of Anatomy and Human Biology, University of Western Australia, Perth, WA, Australia; The McComb Research Foundation, Telstra Burn Outcome Centre, 11th Floor, Royal Perth Hospital, Wellington Street, Perth, WA 6000, Australia.
Unni
Ambili
A
School of Anatomy and Human Biology, University of Western Australia, Perth, WA, Australia.
Keeney
Diane
D
Dept. of Medicine and Biochemistry, Vanderbilt University, Nashville, TN, USA.
Wood
Fiona
F
The McComb Research Foundation, Telstra Burn Outcome Centre, 11th Floor, Royal Perth Hospital, Wellington Street, Perth, WA 6000, Australia; Royal Perth Hospital, Perth, WA, Australia; Princess Margaret Hospital for Children, Perth, WA, Australia; School of Surgery, University of Western Australia, Perth, WA, Australia.
Fear
Mark
M
The McComb Research Foundation, Telstra Burn Outcome Centre, 11th Floor, Royal Perth Hospital, Wellington Street, Perth, WA 6000, Australia. Electronic address: mark@mccomb.org.au.
Dharmarajan
Arunasalam
A
School of Anatomy and Human Biology, University of Western Australia, Perth, WA, Australia.
D017209:Apoptosis / Q000235:genetics; D002454:Cell Differentiation / Q000235:genetics; D002478:Cells, Cultured; D053938:DNA Fragmentation; D000078404:Epidermal Cells; D004817:Epidermis / Q000378:metabolism; D006801:Humans; D015603:Keratinocytes / Q000166:cytology / Q000378:metabolism; D011498:Protein Precursors / Q000096:biosynthesis; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000502:physiology*; D012333:RNA, Messenger / Q000378:metabolism; D000094742:Secreted Frizzled-Related Proteins
D011498:Protein Precursors; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; C118723:SFRP4 protein, human; D000094742:Secreted Frizzled-Related Proteins; C032253:involucrin